US4091399A - Mirror driving device for a single lens reflex camera - Google Patents
Mirror driving device for a single lens reflex camera Download PDFInfo
- Publication number
- US4091399A US4091399A US05/640,894 US64089475A US4091399A US 4091399 A US4091399 A US 4091399A US 64089475 A US64089475 A US 64089475A US 4091399 A US4091399 A US 4091399A
- Authority
- US
- United States
- Prior art keywords
- mirror
- biasing
- driving
- lever
- energy
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
Images
Classifications
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
- G03B19/00—Cameras
- G03B19/02—Still-picture cameras
- G03B19/12—Reflex cameras with single objective and a movable reflector or a partly-transmitting mirror
Definitions
- This invention relates to a single lens reflex camera, and is particularly directed to a mirror driving device in a single lens reflex camera.
- a driving spring which stores energy for the operations of moving the mirror up and down. By releasing a locking key mirror-up and mirror-down operations are performed with the aid of the stored energy of the spring.
- a brake mechanism utilizing an elastomer or rubber or an air damper for absorbing the kinetic energy of the spring driving mirror when the mirror is stopped.
- the kinetic energy of the mirror is at its maximum just prior to the cessation of its motion. Shock and noise are inordinately large.
- the kinetic energy is lost as frictional energy or thermal, and substantial energy is required to re-energize the driving spring when charging the mirror.
- the object of the invention is to overcome the described limitation of the prior art devices, to provide a mirror driving device which requires a small amount of energy for charging or winding it up, and to furnish a device which furnishes a minimum of shock and noise when the mirror is moved.
- the energy of mirror-up is absorbed to utilize it as the energy for mirror-down during the ascending operation of the mirror, and then this energy is substantially absorbed to utilize it as the energy for the mirror-up operation at the phototaking step during the descending operation of the mirror.
- the energy loss is unavoidable, it is necessary to supplement the energy from the external, of which the amount is to compensate the loss of energy, for efficiently prosecuting the mirror-up and mirror-down operation.
- FIG. 1 is a side view of a mirror box in accordance with a first embodiment of the invention
- FIG. 2 is a side view of a mirror box in accordance with a second embodiment of the invention.
- FIGS. 3 to 6 show side views of a mirror box in accordance with a third embodiment of the invention, FIG. 3 showing the state of the device before the shutter is charged, FIG. 4 where the shutter charge is completed, FIG. 5 where the ascension of the mirror is finished, and FIG. 6 the condition where the energy for the operation of the descending mirror is supplemented;
- FIGS. 7 to 10 show of a mirror box in accordance with a fourth embodiment of the invention, FIGS. 7 to 10 corresponding to FIGS. 3 to 6, respectively;
- FIG. 11 is a side view of a mirror box in accordance with a fifth embodiment of the invention.
- a conventional mirror 1 shown in broken lines rotates about the shaft 1b and has a pin 1a.
- the mirror 1 is prevented from upward rotation by a first mirror key 2, and is releasably retained at a position inclined 45° relative to the optical axis.
- the first mirror key 2 is normally biased to counterclockwise direction, and is stopped by the stopper 2a.
- a second mirror key 3 is used for retaining the mirror at its uppermost position, and is normally biased to the clockwise direction and is stopped by the stopper 3a.
- a first driving lever 4 is rotatable about a shaft 4a fixed to the side wall of the mirror box, the side wall corresponding to the paper of the drawing. The upper side surface of the lever 4 abuts on the pin 1a.
- a second driving lever 5 is rotatable about a shaft 5a fixed to the side wall of the mirror box, and the lower side surface of the lever 5 abuts on the pin 1a.
- a stopper 6 is fixed to the side wall of the mirror box and acts to stop the first and second driving levers 4 and 5.
- An energy supplementing lever 7 is movable obliquely in the up and down directions, and is biased downwardly by a compression spring 8.
- the spring 8 is hereinafter referred to as the third biasing spring.
- a first key 9 is normally biased in a counterclockwise direction to prevent the lever 7 from moving downwardly.
- a second key 10 is normally biased in a clockwise direction to prevent the lever 7 from moving upwardly.
- a first biasing compression spring 11 is positioned between the lever 7 and the first driving lever 4 and a second biasing spring 12 is positioned between the lever 7 and the second driving lever 5.
- a stopper 13 is fixed to the side wall of the mirror box to limit the movement of the lever 7.
- a biasing lever 14 is supported at the side of the camera to work the lever 7 upwardly in association with the shutter charge and upon completion of the shutter charge, the lever 14 enables restoring the lever 9 to its original position.
- the state of the elements at their solid line and broken line positions, respectively, as shown in FIG. 1, shows where the shutter charge is completed. From this state, when the shutter is released, the first mirror key 2 rotates in the clockwise direction to release the mirror 1.
- the first driving lever 4 being biased upwardly by the first biasing spring 11 pushes against the pin 1a to elevate the mirror 1. In this ascending operation of the mirror 1, the first driving lever 4 stops upon impact with the stopper 6. With respect to this impact, since the moment of inertia of the first driving lever 4 is small, and the extent of motion is very small, the kinetic energy of the first driving lever 4 before the impact is commensurately small. As a result the shock and noise at such impact are so small as to the almost imperceptible.
- the pin 1a departs from the first driving lever 4 and begins to engage the second driving lever 5. Then, the mirror 1 pushes against the second biasing spring 12 and continues its ascension until it is stopped by the second mirror key 3. At this elevated position, the mirror has rotated 45° from its original stop position. The kinetic energy of the mirror 1 has been converted into the potential energy of the second biasing spring 12 and decelerates the mirror 1. Of course, there is a loss of energy due to friction and the amount of this potential energy is less than the kinetic energy released from the mirror 1 by the amount of energy lost because of friction. When the mirror 1 is retained at its elevated position, or when the ascent is completed, the mirror 1 and the driving levers 4 and 5 are located at the two-dot line positions shown in FIG. 1.
- the energy supplementing lever 7 is released from engagement with the first key 9. Due to the force of the third biasing spring 8, the lever 7 is moved, until such lever engages the stopper 13 and simultaneously is hooked by the second key 10. A portion of the lever 7 at this stage is shown in dotted line.
- the energy stored in the third biasing spring 8 is converted into potential energy for the second biasing spring 12 so that the energy of the latter spring is imparted to the mirror descending operation.
- the second mirror key 3 is released, and the pin 1a is pushed by the force of the second biasing spring 12 and the mirror 1 is lowered.
- the second driving lever 5 impacts on the stopper 6 and stops there. The shock and noise at this impact are very small and almost imperceptible.
- the pin 1a leaves the second driving lever 5 and begins engagement with the first driving lever 4.
- the mirror continues its downward motion while compressing the first biasing spring 11 until the mirror engages the first mirror key 2 after its 45° upon descending travel of 45° and having been restored to the shown original broken line position.
- the mirror is retained at its lowered position.
- the biasing lever 14 is moved to upward position and the supplementing lever 7 is restores to the solid line position shown in FIG. 1. Consequently, the first biasing spring 11 is further compressed, and the energy needed to supplement the energy necessary for the mirror-up operation and the shutter charge is completed.
- a certain amount of potential energy has also been stored in the first biasing spring 11 by the previous downward movement, whereby the supplemented potential energy imparted to such spring by the biasing lever 14 need be but a small amount.
- the subsequent operation is the same as previously described.
- the first and second driving levers of the first embodiment are made as a unitary part.
- the same reference numerals are assigned to the similar elements except for the driving lever and the biasing springs.
- the first, second and third biasing springs are respectively assigned reference numerals 11', 12', and 8', all of the springs being compression springs.
- the driving lever 15 has a slot 15b for receiving therein the pin 1a for the mirror. In the mirror-up operation, the first mirror key 2 is released from the state of FIG. 2, causing the driving lever 15, and therefore the mirror 1, to be rotated by the pulling force of the first biasing spring 11'.
- the second biasing spring 12' is put in tension so that the movement of the mirror is dampened or braked.
- the first biasing spring 11' would accelerate movement of the mirror but for the force of the second biasing spring 12'.
- the force of the latter becomes equal to the force of the former, which is the neutral state.
- the supplementing lever 7 will vary this neutral position between the mirror-up and mirror-down operations, taking the frictional energy loss into consideration.
- the energy supplementing lever 7 In ascending operation of the mirror, the energy supplementing lever 7 is moved so as to locate its position where the neutral position is deviated from the middle point of the total travelling angle of the mirror toward the uppermost mirror position. In such uppermost position, the lever is stopped by first key 9. In mirror-down operation, the lever 7 is moved to locate the position in which the lever is engaged with and stopped by the second key 10 where the neutral position shifted from the middle point of the total travelling angle of the mirror toward the lowermost position of the mirror.
- the driving lever 15 is provided for increasing the freedom of design but it is not necessary.
- the opposite ends of the first 11' and second 12' biasing springs, respectively, are hooked on the pin 1a of the mirror.
- the first and second biasing springs of the first embodiment are made as a unitary or single part.
- the elements common to those of FIGS. 1 and 2 are given the same reference characters.
- the first driving lever 24 and the second driving lever 25 are rotatably supported on the energy supplementing lever 27.
- the lever 27, which is rotatable about the shaft 27a, has a stop 26 thereon located between the levers 24 and 25.
- the reference character 28 designates the third biasing spring, 29 the first key, 30 the second key and 31 the single biasing spring which corresponds to the first and second biasing springs in the first and second embodiments.
- the spring 31 is connected to the first and second driving levers at 24b and 25b, respectively.
- the third biasing spring 28 and the biasing spring 31 are tension springs, respectively.
- the reference character 33 designates the stop for the energy supplementing lever 27, and 34 is the biasing lever provided at the camera body.
- FIG. 3 shows the state where the shutter is not yet charged, or the wind-up lever has not been operated.
- the charging of the shutter is performed by the operation of, for example, the wind-up lever
- the second key 30 is rotated in the direction of the arrow to enable the supplementing lever 27 to rotate
- the biasing lever 34 is moved in the direction of the arrow.
- the lever 27 rotates counterclockwise against the force of the third biasing spring 28 and is engaged with the first key 29.
- the supporting point 24b of the biasing spring 31 on the first driving lever 24 moves close to the pin 1a so that the lever 24 scarcely moves.
- the second driving lever 25, however moves together with the supplementing lever 27 as the lever 25 contacts with the stop 26 so that the biasing spring 31 has tension applied thereto to increase its potential energy for the mirror-up motion.
- FIG. 4 shows the completion of this shutter charging operation.
- the ascending procedure of the mirror is quite similar to that in the first embodiment, but the potential energy of the biasing spring 31 is converted into the kinetic energy of the mirror 1 through the driving lever 24 and during the ascending movement of the mirror 1 this kinetic energy is stored as the potential energy of the one and the same biasing spring 31 through the second driving lever 25, which is the characteristic feature of the embodiment.
- FIG. 5 shows the state where the ascending operation of the mirror is completed.
- the first key 29 is rotated in the direction of the arrow (FIG. 5) and is released from engagement with the lever 27.
- the lever 27 is restored to its before-shutter charging state by the biasing force of the third biasing spring 28.
- the supporting point 25b for the spring 31 on the lever 25 is close to the pin 1a for the mirror so that the lever 25 scarcely moves.
- the supporting point 24b on the lever 24 is moved together with the lever 27 as the lever 24 contacts the pin 26, and the spring 31 is placed in tension so as to increase the downward movement potential energy.
- the stop blades are normally retained at their fully-open position by a biasing member provided at the camera, and when the shutter is released, the biasing force of the biasing member is released so as to obtain a predetermined stop value.
- the stop blades are operated to obtain a predetermined stop value only when the shutter is released. Consequently, in case of the automatic stop operation, a further operation is required to interlock the operation of the biasing member provided at the camera.
- FIGS. 7 to 10 show an embodiment in which the automatic stop operation of the former type is adapted so that the stop blades are normally biased toward a small aperture size.
- the elements common to the first, second and third embodiments bear the same reference characters.
- the first mirror key 2' is normally biased in a clockwise direction so that it is engaged with the projection 1'c provided on the mirror body 1'.
- the first driving lever 44 and the second driving lever 45 are each rotatably supported on the energy supplementing lever 47 as the same as in the third embodiment.
- the lever 47 is rotatably pivoted at one end 46, such end serving as a stop for the first and second driving levers 44 and 45.
- the third biasing spring is shown at 48 and the first key 49 is moved perpendicularly to the plane of the paper.
- 50 is the second key
- 51 is the biasing spring similar to that shown in the third embodiment
- 53 is the stop for the energy supplementing lever 47
- 54 is the biasing lever provided on the camera body.
- a lever 55 is rotatably mounted on the lever 47 for releasing the second key, and the lever 55 is rotated at the beginning of the movement of the biasing lever 54 to release the second key 50.
- a lever 56 is interlocked to operate with the movement of the mirror 1.
- the lever 56 is provided with pins 57 and 58, the former being in the form of a roller for engagement by the levers 44 and 45, the latter engaging a stop 60 as shown in FIG. 8, a mirror interconnecting member 59 connects the mirror body 1' with the lever 56.
- the mirror body 1', the lever 56 and the member 59 are interlocked and together correspond to the mirror 1 in the first, second and third embodiments.
- the stop lever 60 is pivoted about the fixed shaft 56a together with the lever 56 and normally is biased counterclockwise by the spring 61 connected between the mirror interlocking lever 56 and the stop lever 60.
- the shutter actuating lever 62 is located for engagement by the rotatable lever 56.
- the second mirror key 3' is normally biased in the clockwise direction, and has the pin 3'a for engagement by the energy supplementing lever 47 so as to engage with the mirror interlocking lever 56.
- the biasing spring 51, the third biasing spring 48 and the type 61 are of the tension spring. At the state of FIG. 7, the shutter charge is operated. For clarity in illustration FIGS. 7 and 9 show only the necessary elements.
- the lengths of the arms from the point 57 to the points 44a and 45a, where the biasing spring 51 is connected are longer with respect to the first driving lever 44 than with respect to the second driving lever 45, and the lengths of the arms from the point 57 to the supporting shafts 44b and 45b on the energy supporting lever 47 are longer with respect to the second driving lever 45 than with respect to the first driving lever 44 so that the distance between the points 44a and 45a is increased and the biasing force of the biasing spring 51 is further increased.
- This state is shown in FIG. 8.
- the shutter is released, whereupon the first mirror key 2' is released, and the first driving lever 44 biased by the biasing spring 51 becomes rotatable counterclockwise with the shaft 44b as its center of rotation.
- This biasing force causes the roller 57 to rotate the mirror interlocking lever 56 clockwise around the shaft 56a, and the mirror connecting member 59 moves substantially to its uppermost position to raise the mirror body 1'.
- the first driving lever 44 impacts on the stop 46, as previously described in the first, second and third embodiments, and the roller 57 moves away from the first driving lever 44 to press against the second driving lever 45.
- the second mirror key 3' rotates clockwise to stop the mirror interlocking lever 56.
- one end 56b of the mirror interlocking lever 56 presses the shutter actuating lever 62 (FIG. 9) to initiate the running of the shutter.
- the first key 49 is released and the energy supplementing lever 47 rotates counterclockwise.
- the lever 47 abuts with the pin 3'a of the second mirror key to rotate the pin 3'a counterclockwise to release the mirror interlocking lever 56. Consequently, the mirror interlocking lever 56 is rotated counterclockwise by the second driving lever 45 receiving the biasing force of the spring 51 so that the mirror connecting member 59 is lowered to cause the mirror body 1' to descend, as shown in FIG. 10.
- the time to release the second mirror key 3' is different from that in the first, second and third embodiments.
- the second mirror key 3' is released before the completion of the transfer of the supplemented energy for the descent of the mirror from the third biasing spring 48 to the biasing spring 51.
- the moment of inertia of the lever 47 is smaller than the moment of inertia of the mirror system comprising the mirror body 1', the connecting member 49, the interlocking lever 56 and stop lever 60, the time required for releasing the lever 47 from the first key 49 and stopping the second key 50 is only several milli second (ms), while the raised time at the initiation of the movement of the mirror interlocking lever 56 is delayed from such time, there is no trouble even though the mirror interlocking lever 56 is released at the final stage of the rotation of the lever 47.
- FIG. 7 shows the state where the mirror body 1' is retained at its lowered position and is restored to the state where the shutter is not yet charged.
- the effect of the stop lever 60 in the raising and lowering operations of the mirror is more significant where the aperture size is smaller. Where the predetermined value is of the fully opened aperture the effect of the lever 60 is negligible in both the raising and lowering operations. Consequently, the maximum deceleration must be considered in the descending step. More supplementing energy is required for lowering the mirror than for raising the mirror.
- This is different from the first, second and third embodiments. This is controlled by adjusting the contacting-positional conditions of the roller 57 with the first and second driving levers 44 and 45. In other words, the positions of the lever 47, the first driving lever 44 and the second driving lever 45 are adjusted.
- the embodiment shown in FIG. 11 is designed to facilitate the manual operation of raising the mirror.
- This fifth embodiment is a modification of the fourth embodiment and involves a change of the mirror system.
- the mirror spring 63 is connected to the mirror body 1' to normally bias the body 1' toward its lowered position, the pin 1'a being urged into engagement with the lever 56'. Consequently, for the operation of the mirror without shutter release, it is necessary to raise the mirror body 1' against the biasing force of the mirror spring 63.
- the inertia component of the mirror body 1' does not relate with the mirror interlocking lever 56', the potential energy of the spring to be absorbed is less than that absorbed in the showing of the fourth embodiment.
- the third biasing spring 8, 8', 28 or 48 acts on the energy supplementing lever 7, 27, or 47.
- the third biasing lever is not always necessary, it only being necessary that the lever 47 be designed to take the first and second deviated positions from the neutral position.
- the kinetic energy for or during the ascension of the mirror is absorbed to utilize it as the energy for driving the mirror down, and the kinetic energy for or during the lowering of the mirror is abosrbed to utilize it as the driving energy for the next frame so that the energy necessary for the winding becomes small whereby the winding up operation of the wind-up lever becomes light and rapid.
- the shock produced when the mirror is stopped and retained at the uppermost and lowermost positions is decreased, and the noise or sound resulting from the shock is decreased.
- the spring acts as the first and second biasing springs.
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Cameras In General (AREA)
- Springs (AREA)
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JA49-1294 | 1974-12-28 | ||
JP751294A JPS5649338B2 (ja) | 1974-12-28 | 1974-12-28 |
Publications (1)
Publication Number | Publication Date |
---|---|
US4091399A true US4091399A (en) | 1978-05-23 |
Family
ID=11497434
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US05/640,894 Expired - Lifetime US4091399A (en) | 1974-12-28 | 1975-12-15 | Mirror driving device for a single lens reflex camera |
Country Status (3)
Country | Link |
---|---|
US (1) | US4091399A (ja) |
JP (1) | JPS5649338B2 (ja) |
DE (1) | DE2558448A1 (ja) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4480904A (en) * | 1981-11-12 | 1984-11-06 | Canon Kabushiki Kaisha | Anti-mirror-bounce device for single-lens reflex camera |
WO1993025935A1 (en) * | 1992-06-09 | 1993-12-23 | Victor Hasselblad Ab | Camera mechanism displacement means |
Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2952197A (en) * | 1956-06-21 | 1960-09-13 | Canon Camera Co | Reflex mirror operating mechanism coupled with shutter for reflex cameras |
US3653311A (en) * | 1969-03-27 | 1972-04-04 | Nippon Kogaku Kk | Shock absorber (shock isolation device) for mirror of single-lens reflex camera |
US3738246A (en) * | 1971-07-15 | 1973-06-12 | Nippon Kogaku Kk | Mirror shock absorber device for a camera having a quick return mirror |
US3894294A (en) * | 1972-04-24 | 1975-07-08 | Polaroid Corp | Flat torque rate drive system |
-
1974
- 1974-12-28 JP JP751294A patent/JPS5649338B2/ja not_active Expired
-
1975
- 1975-12-15 US US05/640,894 patent/US4091399A/en not_active Expired - Lifetime
- 1975-12-23 DE DE19752558448 patent/DE2558448A1/de active Pending
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2952197A (en) * | 1956-06-21 | 1960-09-13 | Canon Camera Co | Reflex mirror operating mechanism coupled with shutter for reflex cameras |
US3653311A (en) * | 1969-03-27 | 1972-04-04 | Nippon Kogaku Kk | Shock absorber (shock isolation device) for mirror of single-lens reflex camera |
US3738246A (en) * | 1971-07-15 | 1973-06-12 | Nippon Kogaku Kk | Mirror shock absorber device for a camera having a quick return mirror |
US3894294A (en) * | 1972-04-24 | 1975-07-08 | Polaroid Corp | Flat torque rate drive system |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4480904A (en) * | 1981-11-12 | 1984-11-06 | Canon Kabushiki Kaisha | Anti-mirror-bounce device for single-lens reflex camera |
WO1993025935A1 (en) * | 1992-06-09 | 1993-12-23 | Victor Hasselblad Ab | Camera mechanism displacement means |
US5598244A (en) * | 1992-06-09 | 1997-01-28 | Victor Hasselblad Ab | Camera mechanism displacement means |
Also Published As
Publication number | Publication date |
---|---|
JPS5178320A (ja) | 1976-07-07 |
DE2558448A1 (de) | 1976-07-08 |
JPS5649338B2 (ja) | 1981-11-20 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US2730025A (en) | Photographic reflex cameras | |
US4091399A (en) | Mirror driving device for a single lens reflex camera | |
US3221626A (en) | Mechanism for operating the reflecting mirror of single lens reflex cameras | |
US4458998A (en) | Mechanical shock absorbing device of a camera | |
US4385820A (en) | Mirrorraising motion braking mechanism | |
US4003066A (en) | Mirror operating arrangement of single lens reflex camera | |
US3913117A (en) | Focal plane shutter for photographic camera | |
US3653311A (en) | Shock absorber (shock isolation device) for mirror of single-lens reflex camera | |
US3672282A (en) | Device for driving camera shutter curtains | |
US5598244A (en) | Camera mechanism displacement means | |
US3337146A (en) | Automatic film threading mechanism | |
US4245905A (en) | Blade actuating device for focal plane shutters | |
US4327982A (en) | Device for suppressing mirror bounce in single lens reflex camera | |
US3731609A (en) | Mirror mechanism for a single-lens reflex camera | |
US4179201A (en) | Lens stop braking in automatic exposure cameras of stop value control type | |
US4192598A (en) | Mirror driving device for use in a single lens reflex camera | |
US5294952A (en) | Apparatus for driving mirror of camera | |
US4420235A (en) | Shutter drive safety device for a camera | |
US4469420A (en) | Device for preventing bounce of the movable mirror in a single lens reflex camera | |
US3640202A (en) | Single lens reflex camera | |
US4306797A (en) | Electromagnetically driven shutter | |
US4220408A (en) | Shutter release mechanism | |
US4075646A (en) | Multi-exposure device for camera | |
US3741091A (en) | Single blade electric shutter | |
US2738716A (en) | Control or release device for photographic cameras |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
AS | Assignment |
Owner name: NIKON CORPORATION, 2-3, MARUNOUCHI 3-CHOME, CHIYOD Free format text: CHANGE OF NAME;ASSIGNOR:NIPPON KOGAKU, K.K.;REEL/FRAME:004935/0584 |